When cutting and removing casing or tubulars, a rotary cutter is employed that is driven from the surface or downhole with a downhole motor. The cutting operation generates some debris and requires circulation of fluid for cooling and, to a lesser extent, debris removal purposes. One way to accommodate the need for circulation is to avoid sealing the tubular above the cutter as the cut is being made. In these cases also the tubular being cut can be in compression due to its own weight. Having the tubing in compression is not desirable as it can impede the cutting process making blade rotation more difficult as the cut progresses. Not actuating a seal until the cut is made (as shown in U.S. Pat. No. 5,101,895), in order to allow for circulation during the cut, leaves the well open so that if a kick occurs during the tubing cutting it becomes difficult to quickly get control of the well. Not gripping the cut casing until the cut is made, so that the cut is made with the tubular in compression, is shown in U.S. Pat. No. 6,357,528. In that tool there is circulation through the tool during cutting followed by the dropping of an object into the tool to allow the tool to be pressured up, so that the spear can be set after the cut is made.
Sometimes the casing or tubular is cut in a region where it is cemented, so that the portion above the cut cannot be removed. In these situations another cut has to be made further up or down the casing or tubular. Some known designs are set to engage for support with body lock rings. In this case, there is but a single opportunity to deploy the tool in one trip. In the event the casing or tubular will not release, these tools have to be pulled from the wellbore and redressed for another trip.
While it is advantageous to have the opportunity for well control in the event of a kick, the setting of a tubular isolator has in the past presented the associated problem of blocking fluid circulation as the cut is being made.
Another approach to making multiple cuts is to have multiple assemblies at predetermined spacing so that different cutters can be sequentially deployed. This design is shown in U.S. Pat. No. 7,762,330. It has the ability to sequentially cut and then grip two cut pieces of a tubular in a single trip, and then remove the cut segments together.
U.S. Pat. No. 5,253,710 illustrates a hydraulically actuated grapple that puts the tubular to be cut in tension so that the cut can be made. U.S. Pat. No. 4,047,568 shows gripping the tubular after the cut. Neither of the prior two references provide any well control capability.
Some designs set an inflatable packer, but only after the cut is made, so that there is no well control as the cut is undertaken. Other designs are limited by being settable only one time, so that, if the casing will not release where cut, making another cut requires a trip out of the well. Some designs set a packer against the stuck portion of the tubular as the resistive force. This method puts the tubular being cut in compression and makes cutting more difficult. Some designs use a stop ring which requires advance spacing of the cutter blades to the stop ring. In essence, the stop ring is stopped by the top of a fish so that if the fish will not release when cut in that one location, the tool has to be tripped out and reconfigured for a cut at a different location.
The latter design is illustrated in FIG. 1. The cutter (that is not shown) is attached at thread 10 to bottom sub 12. Mandrel 14 connects drive hub 16 to the bottom sub 12. Stop ring 18 stops forward travel when it lands on the top of the fish (that is also not shown). When that happens, weight is set down to engage castellations 20 with castellations 22 to rotate a cam assembly 24 such that a stop to travel of the cone 26 with respect to slips 28 can be moved out of the way. A subsequent pickup force will allow the cone 26 to go under the slips 28, which will grab the fish and hold it in tension while the cut is made. Again, the cut location is always at a single fixed distance to the location of the stop ring 18.
Some designs allow a grip in the tubular to pull tension without the use of a stop ring but they can only be set one time at one location. Some examples are U.S. Pat. Nos. 1,867,289; 2,203,011 and 2,991,834. U.S. Pat. No. 2,899,000 illustrates a multiple row cutter that is hydraulically actuated while leaving the mandrel open for circulation during cutting.
A more recent example of a tubular cutter is found in WO2011/031164 and uses spaced slips about a sealing element for a tubular cutting tool. It has more limited functionality than the present invention, especially with regard to cutting-in-tension and providing well control if there is a well kick.
While the locking feature of the invention will be described in the context of the preferred embodiment that is a rotary tubular cutter, the applications for the lock assembly goes beyond such a preferred application and are applicable to subterranean tools that are resettable that need to be locked in a set position, and that are releasable to be reset in the same trip or pulled out of the hole. In essence the lock assembly locks a moving component to a stationary one to hold the set position and the lock can be defeated and reset so that it can lock the downhole tool again at the same or a different well location without having to come out of the hole.
A resettable lock in the context of a downhole isolation valve is shown in U.S. Pat. No. 7,210,534.
In a tubular cutter embodiment of the invention there is the ability to make multiple cuts in a single trip while providing a spear that is mechanically set to grab above the cut location inside the tubular being cut. Additionally, the packer can be deployed before the cut is started, in order to provide well control and bypass-circulation through the tool during the cut, so other downhole equipment can also be operated. The tubular to be removed is engaged before the cut and put in tension while the cut is taking place.
In other versions the lock can be associated with a resettable packer, a ported sub with a sliding sleeve valve, screen sections with associated valve members or any other tool where movement of a movable member with respect to a stationary member occurs during the setting of the tool. The other versions of this device also possess the ability to lock their position and then release their position in a manner in which they can be locked again in the same trip or alternatively removed from the wellbore.
These and other features of the present invention will be more apparent to those skilled in the art from a review of the detailed description and the associated drawings while understanding that the full scope of the invention is to be determined from the appended claims.